Re: [PATCH v3 3/4] rust: validate: add `Validate` trait

[Benno Lossin <benno.lossin@proton.me>]

On Mon Apr 21, 2025 at 6:47 PM CEST, Guangbo Cui wrote:
> Really cool patch! I got a few thoughts below.

Thanks!

>> +    /// Validate the underlying untrusted data.
>> +    ///
>> +    /// See the [`Validate`] trait for more information.
>> +    pub fn validate_mut<'a, V: Validate<&'a mut Self>>(&'a mut self) -> Result<V, V::Err> {
>> +        V::validate(&mut self.0)
>> +    }
>>  }
>
> The `validate_ref` and `validate_mut` functions should just call `V::validate(self)`
> directly, since self is an Untrusted<T>, and you already implemented ValidateInput for it.
> Calling `V::validate(&self.0)` would cause a type mismatch error.

Ah good catch, but the fix should be a different one. I intend to remove
the `Untrusted` wrapper in the input to `Validate::validate`, as
otherwise one would not be able to access the underlying value.

Maybe I don't need the `ValidateInput` trait after all. So the signature
of `validate{,_ref,_mut}` should ask for `V: Validate<{T, &T, &mut T}>`
instead.

---
Cheers,
Benno